I picked this up a few days ago: PanasonicBoombox.jpg - Google Drive
It's a Panasonic RX 5085. Sounds surprisingly decent, maybe a little light on bass, but I don't mind. Contrary to my username, I don't know anything about these boxes. 🙂 I did have a few questions though, so enlighten me.
1. How does the "ambiance" mode on this thing actually work? There's mono, stereo, and ambiance. Flipping it to that mode seems to artificially expand the sound stage and create this fake "surround sound" effect. I don't really like it because it makes the music sound weird, but I am curious, how does it actually modify the signal to achieve this effect?
2. What type of enclosure do the drivers sit in? From what I could tell, there's no ports, but the design looks too leaky to be a sealed enclosure. Does this mean it's open baffle like most car speakers?
3. I was planning to open and clean everything up inside. Will adding a bit of polyfill or other dampening material inside the enclosure improve sound quality and bass extension? Or will this cause other problems I'm not aware of?
4. Do these boomboxes have the same issue with the worn foam surrounds as bookshelf speakers at the time? Will I have to replace the surrounds soon? Or are they rubber or something like most of the modern stuff?
It's a Panasonic RX 5085. Sounds surprisingly decent, maybe a little light on bass, but I don't mind. Contrary to my username, I don't know anything about these boxes. 🙂 I did have a few questions though, so enlighten me.
1. How does the "ambiance" mode on this thing actually work? There's mono, stereo, and ambiance. Flipping it to that mode seems to artificially expand the sound stage and create this fake "surround sound" effect. I don't really like it because it makes the music sound weird, but I am curious, how does it actually modify the signal to achieve this effect?
2. What type of enclosure do the drivers sit in? From what I could tell, there's no ports, but the design looks too leaky to be a sealed enclosure. Does this mean it's open baffle like most car speakers?
3. I was planning to open and clean everything up inside. Will adding a bit of polyfill or other dampening material inside the enclosure improve sound quality and bass extension? Or will this cause other problems I'm not aware of?
4. Do these boomboxes have the same issue with the worn foam surrounds as bookshelf speakers at the time? Will I have to replace the surrounds soon? Or are they rubber or something like most of the modern stuff?
Hi! I've still got my old Panasonic 'boombox'. Recently changed the cassette drive belt and it's working good as new!
- I suspect the ambience mode reverses the phase of one of the speakers so that the sound appears to 'spread out'. In that case you will find a central image hard to locate.
- The enclosure will simply have a ventilated back. There will be no special bass loading such as reflex ports and that's why the bass response is so limited.
- Sticking some dampening material to the internal walls will help prevent the cabinet resonating/vibrating, but will not increase the bass response.
- The speaker surrounds on these are simple corrugated paper. There is no problem with foam rot or rubber perishing.
Room loading is your friend with these, helps with bass and with distortion as you crank it up.
On the floor against the wall, on a counter or table in the corner, one boundary helps, but two is the goal, three is a bonus.
Over the years, many enjoyable hours in workshop or garage, or camp.
On the floor against the wall, on a counter or table in the corner, one boundary helps, but two is the goal, three is a bonus.
Over the years, many enjoyable hours in workshop or garage, or camp.
Adding reverb may be the thing Allen.
Searching brings up no information on the effect of ambience switches, but 'Sound on Sound' magazines's glossary of technical terms defines ambience thus:
Ambience — The result of sound reflections in a confined space being added to the original sound. Ambience may also be created electronically by some digital reverb units. The main difference between ambience and reverberation is that ambience doesn't have the characteristic long delay time of reverberation; the reflections mainly give the sound a sense of space.
Searching brings up no information on the effect of ambience switches, but 'Sound on Sound' magazines's glossary of technical terms defines ambience thus:
Ambience — The result of sound reflections in a confined space being added to the original sound. Ambience may also be created electronically by some digital reverb units. The main difference between ambience and reverberation is that ambience doesn't have the characteristic long delay time of reverberation; the reflections mainly give the sound a sense of space.
Thanks! Btw, where did you find your cassette belts? I haven't tried playing a cassette on mine yet, but I'm sure the belt is on its way out...
Not your country of location, but I get my belts here: https://cpc.farnell.com/c/audio-visual/av-spares/prl/results/3
Not likely, reverberation was very costly in the mid 1980s, and does not result in that "sound from everywhere but the two speakers" effect the Ambience circuit does.
More likely a short analog "bucket brigade" delay applied to the both the L/R signal, through a type of M/S processing, mixed back to each, resulting in a comb-filtered output artificially expanding the stereo.
An even "wider" version of "mono reprocessed for stereo sound" or Duophonic sound ;^).
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Ambiance on portable devices is usually done by adding some -left to the right and some -right to the left which has the effect of expanding the image but destroys the centre image.
I see, guess it must not have been very popular, I don't see them on portable devices today.
Old 80's Panasonic Boombox Pt. 2
Sorry, last set of questions, I promise. I finally had a chance to open the box up which sparked a few more questions. The box is a Panasonic RX 5085. Sorry if these are stupid questions or very obvious, I grew up in the 2000's so I haven't seen a lot of this stuff.
1. So I thought the microphones were fake and nothing was behind the grills since there was no specific switch to record from the mics. After taking the cover off, they were indeed there though. How do you record from the built in mics? I don't see a specific button to push, or anything to switch to, how does it work? And the mic line in jacks in the rear, I'm assuming they bypass the internal mics?
2. This thing has tweeters but they seem big for tweeters and look more like small fullrange drivers, or mid drivers. It looks like it has a first order "crossover" if you can even call it that. The woofer seems to run full range. So are these real tweeters? Or are they really more just full range drivers with a low "crossover" point?
3. How do I know when the cassette belts are worn? They don't look melted away or anything, but they do feel a little "loose" and soft. I feel this thing's been opened up before in the past, maybe for servicing, but I'm not entirely sure. If I try and play a cassette to check, is it immediately going to eat up the tape?
4. 20200520_102434.jpg - Google Drive
So this thing ^^ seems to be dying because it doesn't take power from 8 d cell batteries anymore. I'm not concerned because I was going to swap it to an 18650 lithium battery anyways. But what's the technical term for this board? I'm curious as to how it actually works, since it looks like an older version of a switching power supply to me.
Sorry, last set of questions, I promise. I finally had a chance to open the box up which sparked a few more questions. The box is a Panasonic RX 5085. Sorry if these are stupid questions or very obvious, I grew up in the 2000's so I haven't seen a lot of this stuff.
1. So I thought the microphones were fake and nothing was behind the grills since there was no specific switch to record from the mics. After taking the cover off, they were indeed there though. How do you record from the built in mics? I don't see a specific button to push, or anything to switch to, how does it work? And the mic line in jacks in the rear, I'm assuming they bypass the internal mics?
2. This thing has tweeters but they seem big for tweeters and look more like small fullrange drivers, or mid drivers. It looks like it has a first order "crossover" if you can even call it that. The woofer seems to run full range. So are these real tweeters? Or are they really more just full range drivers with a low "crossover" point?
3. How do I know when the cassette belts are worn? They don't look melted away or anything, but they do feel a little "loose" and soft. I feel this thing's been opened up before in the past, maybe for servicing, but I'm not entirely sure. If I try and play a cassette to check, is it immediately going to eat up the tape?
4. 20200520_102434.jpg - Google Drive
So this thing ^^ seems to be dying because it doesn't take power from 8 d cell batteries anymore. I'm not concerned because I was going to swap it to an 18650 lithium battery anyways. But what's the technical term for this board? I'm curious as to how it actually works, since it looks like an older version of a switching power supply to me.
Integrated circuit reverbs would be relatively expensive when first introduced.
Why don't you ask audiotechnics about his IC? I'm dying to find out what it does!😉
Can you see the 'Am' for 'Ambience' switch next to the IC in the circuit diagram he provided?